Spark plug



March 11 1924., 1,486,459

F. A. RUDOLPH SPARK PLUG Filed Feb. '7. 1921 Zak/.2,

Patented Mar. 11, 1924.

FLAVEL A. RUDOLPH, OF ST. LCUIS, MISSOURI.

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Application filed February 7, 1921. Serial No. 442,995.

To all whom it may concern:

'Be it known that I, FLAVEL A. RUDOLPH, a citizen of the United States, residing in the city of St. Louis and State of Missouri, have invented certain new and useful Improvements in Spark Plugs, of which the following is a specification. g

My invention relates to spark plugs for internal combustion engines, and, more particularly to a ground electrode therefor.

The object of my present invention is to provide a spark plug with a ground electrode capable of oscillating, or swinging movement due to the jar, or vibration of a vehicle, thereby insuring a clean ground electrode by preventing the accumulation of oil and carbon formation at the spark gap formed between the ground electrode and V the center electrode.

A still further object of the invention is to provide the upperconcaved surface of theground electrode with a plurality of suitably spaced transverse notches to form tooth like ground electrode projections, or fingers.

7 With the above and other objects in view,

the invention consists in the novel features of construction, combination and arrangement of arts hereinafter more fully described and finally pointed out in the claims hereto appended.

Referring to the accompanying drawings forming a part of this specification wherein like characters of reference denote similar parts throughoutthe several views:

Fig. 1, is a side elevation of a spark plug provided with a ground electrode constructed and connected to the conducting shell in accordance with my invention.

Fig. 2, is also a side elevation thereof. Fig. 3, is an enlarged detail of the ground electrode, clearly showing its relation with the center electrode. 7

7 Fig. 4, is a detail of the ground electrode and its supporting bail, or hanger.

Referring to the accompanying drawings,

. the reference character 1 designates the usual standard conducting shell having the screw threaded lower end 2. 3 indicates the insulator, or porcelain, 4 the center electrode, and 5 the clamping collar.

The ground electrode A comprises a suitable metallic body 6 having a curved, or concaved upper surface which surface is provided with a plurality of suitably spaced transverse grooves, or notches 7 to provide ed to, and carriedby means of a suitable bail shaped hanger, or conductor 10 which conductor is provided at its extremities with the opposed inwardly projecting cars 11 for hinged connection with the openings 12 in the lower portion 2 of the conducting shell 1. The ground electrode A, it will be observed, is suspended to swing in an arcuate path a predetermined distance below. the lower end of the central electrode t, thus eliminating the usual accumulation'of carbon deposit. which bridges and thereby short circuits the electrodes of the standard type of spark plug. It is evident that when a vehicle is in motion, the vibration and movements thereof will cause the ground electrode to swing regardless of the position of the vehicle at any time and by reason of gravity and capillary attraction, a drop of oil or carbon bridging the electrodes would be instantly drawn away from the point of the center electrode leaving the the same distance from the center electrod as the ground electrode swings in an arcuate path, as will be clearly understood from Fig. 3. The spaces 7 between the ground electrode teeth 8, act so to speak, as drains for the teeth should they become covered with oil wet carbon deposits from any cause. Thus, by keeping the upper surface portion of the teeth practically free from oil, a hot and intense spark is assured. The oil drain spaces 7 of the ground electrode A provides the ground electrode with a greater surface area, thusis afforded in the standard form of ground electrode, and, being extremely hot at all times, reduces the possible chances of carbon formation Suficient to bridge and short circuit the electrodes, as is manifest. The slightest swinging movement of the ground electrode A with relation to the center electrode, or vice-versa, it will be observed, would break or destroy any carbon or oil deposit that would attempt to bridge the spark gap and short much greater than is generally used i n metallic volume, will absorb and holdasuflicient heat to quickly change to gas any non vaporized gasoline that may be thrown on same and being in so close proximity. of the electric spark, ignites the charge instantly.

It will be observed from Fig. 3, that the ground electrode is limitedin its swing ing movement in either direction due to the ground electrode striking the lower face 13 of the conducting shell which acts as a stop for the ground electrode thereby insuring the proper spark gap even at the extreme swinging movement of the ground electrode.

The many advantages of the 'hereindescribed invention will readily suggest themselves to those skilled in the art to which it appertains. I

I do not wish to be understood as having limited myself to the exact details of construction shown and described, but desire to have it understood that the invention I have shown in the drawings is merely illustrative, as it is manifest that various minor changes may be made in the form, shape and particular arrangements of parts without departing from the spirit of my invention, hence I reserve the right to make any such changes, or modifications as may fairly fall within the scope of. the appended claims when fairly construedf What I claim is:

1. In a spark plug, the combination of a conducting shell, an insulating core, a center electrode and a ground electrode depending from the lower end of the conducting shell pivotally connected thereto to freely swing in an arcuate path below the lower end of the center electrode, and a plurality of spaced tooth like members the swinging bail member.

"spaced teeth.

.4. In combination with a conducting shell, an insulator and a central electrode, of a ground electrode suspended from the lowerend Iofthe conducting shell and caable. ofs'wingin'g movement in an arcuate pathbelow the lower end of the fixed central electrode and the lower face of said conducting shell acting as a stop to limit a movement of the ground electrode in 'eit er direction.

'5. A terminal fortspark plugs compris' ing a bail shapedmemberand a metallic niember having a concave'd, serratedupper face fixed thereto midway the ends of said 6 A ground terminal for. spark plugs comprising a U-shaped 'bailhaving o posed terminal ends directed toward each other, afi'at. member having its upper face concaved' fixed midway'its ends to said bail and saidmember beingprovided with a plurality'of spaced tooth projections, the outer faces of which lie in a curved line.

In testimony whereof, I have hereunto signed name to the specification;

L vEL A. RUDOLPH. 

